Variable-speed driving mechanism.



No. 833,974- PATENTBD 00T. 23, 1906.-

R. M. RUGK.

l VARIABLE SPEED' DRIVING [WISGHABIISM-y APPLIOATION FILED APR.9,1906. I

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I PATENTBD OCT. 23,1906.

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A rra/amvb UNITED .sTATns 4PATENT onnrong- "RicHARDMATTi-mws RUGK, or LONDON, ENGLAND.

i VARIABLE-SPEED DRIVING MEoHANlsM.

Specicaton-of Letters Patent.

Patented Oct. 23, 1906.-

y Apjpiication filed April 9, i906.A serial No. 310,696.

the following is a specification.

4specially for use on motor-cars.

vThis invention relates to variable-speed driving mechanism, more particularly such as is used in the transmission of power from high-speed motors; and ithas for its object to provide apparatus of the kind referred to which shall combine the advantages (with regard to positive driving and graduated alteration of speed ratio) and avoid the disadvantages (with regard to shock and slip) incidentalto the use of ltoothed-wheel gearing and of conoidal friction-pulley variablespeed mechanism, respectively.

The invention will be described with referenceto the accompanying drawings, where- 1n-.

Figure 1 represents in sectional-plan a form of the improved driving-gear designed Fig. 2 is a partialend view'of` a so-called "toothed cone. Fig. 3 is a part section of the apparatus on line 3 3 of Fig. 1, the same being shown to larger scale.

According to the present invention, one member of the variable-speed mechanism consists of a'series (A A2 A3, &c.) 'of rings of bevel-teeth fixed side by side upon a shaft B, successive rings having progressively-varying numbers ofteeth 0I equal pitch and the diameters of successiveV rings "A A2 A3, &c., varying progressively in such ratio that the series of rings together constitute what may be termed a toothed cone A, wherein successive rings have theipitch-cone of their teeth coincident ywith successive zones of a single cone, constituting what may be termed thepitch`-surface of the so-called toothed" coneA. The other member of the variable-speed mechanism consists `of a toothed pinion C, having teeth adapted to gear with those of the so-called cone, this inion being splined upon a shaft D, which the cone. Hence motion may be transmitted between themembers A and C of the variable -speed mechanism in' any speed ratio corresponding to the ratio between the number of teeth in the pinion C and the number in any one of the rings of teeth constituting the cone A, according to the position for the time being of the pinion lengthwise of the cone.

In order that the pinion C may be so moved Valong its shaft D as to be brought vinto gear with successive ringsv of teeth on the cone i while both members A and C of the gear are rotating, the rings of teeth constituting the cone are arranged in such angular relation to one another about their common axis that, ,as indicated in Fig. 2, all the rings have one tooth a (or space between two adjacent teeth) alined in a row which lies in one plane passing through the axis of the cone, so that when during the revolution of the cone said plane coincides with the plane wherein the axes of the'cone A and pinion C both lie the pinion may without shock be moved out of gear with that ring of teeth with which it is rangement thus permits of the pinion being momentarily in gear with twol adjacent rings of teeth at one and the same time instead of necessitating the pinion being thrown entirely out of gear with one ring before being throwninto gear with another. 'Hence successive rings of teeth may be.' closely juxtaposed, as shown, yand the movement whereby the pinion is shifted lengthwise of the cone in order to alter the ratio of the gearing, although in reality intermittent, has almost the smooth character proper Ito unbroken continuity.

A single step of the pinion C lengthwiseof the cone would usually (and especially'where the speed of rotation is high) be as lmuch as could be accomplished during a single revolution of the cone g but where,'as in the cone shown in Fig. 2, there are, sa three equidistant points in the circum erence of the cone whereat all the rings A A2 A3, &c., of teeth have a tooth a lying in the same plane, a step in either direction may be performed by the pinion C each time one of said three rows of alined teeth@ comes into 'the common plane of the shafts B and D. In any case means are provided whereby a step-by-step movement in either direction longitudinally of its own axis to an'extent corresponding (in the case of each step) to the breadth of one loo ' the screw-shaft E, so 'that the nut F receives 'its intermittent movement always at the -the. pinion, so that movement of the nut lengthwise of the screw-'shaft E will be communicated to the pinion. The screw-shaft E is'adapted when revolved to communicate to the nut F once during a portion of each revolution longitudinal movement to an extent corresponding to the breadth of one ring of teeth of the cone A, and means are provided whereby when it is desired to vary the ratio between the two members of the gear the' screw-shaft E may be caused to rotate in time with the revolution of the cone A in a direction to propel t-he nut F toward that point in its travel corresponding to that ring of teeth. with which the pinion C must be brought into gear in order to effect the necessary alteration in speed ratio, said means being also adapted to enable the nut F to be arrested when the pinion C has been brought into gear with the required ring of teeth. To these ends the screw-shaft E has a thread which throughout the greater part of each convolution lies, as at e, in one plane perpendicular to the axis of the screw, the oblique (or movement-producing) part e of the convolution occupying a relatively small portion of the circumference, so that the screw, although revolved continuously, will transmit motion to the nut F only intermittentlythat is to say, during that part of each revolution which corresponds to the angular amplitude of each part c ofthe thread. All the inclined (or movement-producing) parts e of successive eonvolutions of the thread occupj7 the same angular position about the axis of same point in the rotation of the screw, which point is arranged to occur simultaneously with the moment of coincidence between that axial plane of the cone A wherein 'lie the teeth a of each ring of teeth and the common plane of the shafts B and D.

The nut F may have in place of the usual internal thread a stud adapted to engage between adjacent threads of the screw E or a yrow, as f f2 f3, of such studs in alinement with one another lengthwise of the screw, as shown. In such case the inclined (or movement-producing) parts of the eonvolutions are omitted, as at e2, between the terminal grooves e3, wherein the studs f f 2 7(3 engage when the nut F is at either end of its travel and also between the innermost of said terminal grooves e3 and that groove e4 of the screw which is adjacent to the first movement-producing convolution cf of the screw-thread, so that the nut F when brought to either end of its travel will remain stationary notwithstanding continued rotation. of the screwshaft, but will nevertheless be free to be moved in the reverse direction when required.

For the purpose of starting the nut on its travel from either end a rod F is mounted to slide in guides parallel to the axis of the screw-shaft E, so as to be capable of participating to a limited. extent in the travel of the nut, the rod F carrying two collarsf, so placed as to be respectively encountered by an arm f4 on the nut when the latter completes the last step of its travel in either direction. The rod F has therefore a stroke equal to the length of one step of the nut F and when at either limit of its movement is adapted to receive from the hand of the person controlling the apparatus-as, for example, through a rock-shaft and forked lever, as at FZ-momentary pressure in a longitudinal direction sufficient to cause that one of the studs f f 2 f which for the time being is innermost to pass from that terminal groove c wherein it has been stationary to the next groove e4 at the moment when the gap c in the corresponding thread is brought by the revolution of the screw-shaft opposite to the stud. When the stud in question has passed into the groove e4, the revolution of the screw-shaft E in the corresponding direction will cause the nut to automatically continue its travel as far as the opposite end of the threaded portion of the screw-shaft or until the rotation of said shaft is arrested, as hereinafter described.

rlhe ratio between the diameters of the respective members A and C of the variablespeed gear may be made to suit the circumstances of each case, and either of said ineinbers may be the driving member. ln the example illustrated the cone A is the driving member and the pinion C the driven member, while equality of ratio is the lowest gear used and is therefore that at which the heaviest work can be performed. rl`he shaft l), upon which the pinion C is splined, is coupled at one end to the usual Cardan shaft G by means of the universal joint g and is journaled at the opposite end d in a tubular shaft or sleeve H, which is driven through the universal joint j from the high-speed-motor shaft J, the sleeve H being in turn ournaled in the framing I of the apparatus, as shown at 7L.

In normal forward running the cone-shaft B is driven from the high-speed sleeve H, but at slower speed, by means of a toothed pinion K, splined on the sleeve and in gear with a larger toothed. wheel IC, fast on the coneshaft. For backward running the pinion l is slid along the sleeve H-as, for example, by means of a rock-shaft and forked lever, as at IOO c wheel E.

K2`so as to be thrown out of gear with wheel K and into gear with an idle wheel L, turning (upon a stud'l) as one with a pinion L", which is constantly'ingear with a wheel L2, fast on the cone-shaft B.- When the pinion K is in a position midway between the wheels pinion K is provided with clutch-teeth k,

adapted to engage ywith the teeth m lof a vclutch member M, fast on the shaft D beyond the end of the sleeve II`,so thatby sliding the pinion K far enough in the corresponding direction sleeve H' and shaft D will be coupled together.l 1

The rotation of the screw-shaft E in the one or the other direction, as required, is effected fromthe cone-shaft B by means of a toothed' pinion B', fast on the latter and constantly connected, through the medium of an idle wheel D', running loose on the shaft D, with wheels E' and E2, running loose on the screw-shaftE, the wheel E gearing directlyv with wheelD, so as to be rotated in. one direction, while the wheel E2is rotated through an intermediate wheel E3 (indicated by dotted linesiin the opposite direction to The wheels E' E2 are also slidable u onthe screw-shaft E" and'providedwith c utch-teeth n n2, respectively adapted to be engaged. with-clutch members N' N2, fast on said shaft, the wheels being movable lengthwise of the shaft-by means of clutch-forks n, attached to a sleeve N, slidable upon the hrod F and adapted to be actuated by hand from any convenient point-as, for example, thrugh a rock-shaft and forked lever, `as

It is obviousthat the rotation of the screwshaft E must be started and stopped only at such timesas will cause or permit the longitudinal movement of the nut F to concur with the coming of a row of alined teeth a in all the rings A A2 A3, &c., into the common lane of the shafts B and D; To insure t is the wheels B', D', E', E2, and Ed are geared together in such a ratio relatively to the number of teeth in the clutch members N N2 that the throwing `of the clutch-teeth 'n' or n2 into this purpose the sleeve N is provided with a stud e, which projects so as to intermesh alternatively with one or other Aofa'se'ries of three peripheral grooves o 02.03 on a bar'rel O, rotating on an axis paralleltothat o f the sleeve'. The groovesv o 02 03, which are the same distance apart as arey the three ositions of the sleeve N, are separated by-col ars 1)"202, each of which has a gapV p for the passage of the stud o, and the barrel O isl constantly rotated-as, for example, by a wheel P, fasten L the barrel and gearing with an idle wheel P', runningloose on 'the' sleeve N and driven by the wheel' E2-ata speed ratio relatively to the speed of rotation of the wheels E E2 such4 that the stud o can only pass through a gap p from either of the extreme grooves ov oa into the middle groove 02 at the proper moment for stopping the rotation of the screw-shaft E. The two gaps p are situated at o posite ends of a diameter of the barrel O, so t at the sleeve N can only be shifted at one time a distance equal tothat between the groove o2. and one or other of the grooves o o3. further 'means of insuring the completion when once begun of the clutching or un- Asak clutching movement of the Wheels E E2 the i stud ois made of cylindrical or rounded form and the collars p p2 at the sides of each gap p are formed with a sharp or wedge-shaped edge, as indicated, while as an additional precaution the sleeve N may be engaged at each of its three positions by a spring-jumper p3 or equivalent device. v

. Q is an index or pointer movable as one loo' with the nut F, so as by exhibiting the posil tion of the latter relatively to a fixed scale. g to show the position of the pinion C lengthwise of the cone A, and consequently the exact speed ratio at which the gear is at any moment running.

I claim-- 1. The improved variable-speed mechanism formed by the combination with a shaft B of a toothed conoidal drumI composedof'a series of bevel-gears A', A2, &c., juxtaposed and fast on said shaft and having progressively-varying numbers of,` teeth which are of equal pitch, the adjacent teeth of the sev-y eral gears being alined so as to form a row lying in the same lane with the axis of shaft B, a -second sha t D inclined to' the firstnamed shaft B, but in the same plane theresisting in the combination of a so-called toothed cone constituted by a series of juxtaposed rings of bevel-teeth of equal pitch 'mounted to turn as one about a common axis,

the number of teeth in successive rings varying progressively in such ratio that the pitchcones of successive rings coincide with successive zones of a single cone constituting the pitch-surface of the so-called toothed cone and one tooth of all the rings being alined to form a row lying in one plane passing through said axis 5 a shaft journaled to rotate in bearings in the same plane with the aXis and parallel to the bounding-surface of the cone; a toothed pinion splined upon said shaft and adapted to gear with the several toothed rings of the cone alternatively; a screw journaled in bearings arallel to said shaft and having a thread W ose pitch corresponds to the distance apart of the toothed rings of the cone, and each of whose convolutions, for the greater portion of its circumference, lies in a plane perpendicular to the aXis of the screw; there being gaps in the terminal convolutions of the screw-thread; a nut adapted to work upon and held against rotation relatively to said screw and so coupled to said pinion as to be capable of communicating thereto its own. traversing movement lengthwise of the screw; gearing for rotating the screw in either direction alternatively and at such speed relatively to that of the toothed cone that the nut may receive traversing movement along the screw in the corresponding direction step by step at those moments only when the row of alined teeth in all the rings ofthe cone are brought into the common plane ofthe axes of the cone and shaft; and means whereby, when the nut is not being thus traversed along the screw, the rotation of the latter may be start ed in either direction and stopped independently of the revolution of the cone and shaft, substantially as s eciiied.

RICHAR MATTHEWS RUCK.

Witnesses:

GEORGE ERNEST MINTERN, WALTER J. SKERTEN. 

